by Nigel Percy

Created on: July 14, 2009

Optics, or the study of the behavior and the properties of light, has a long history of investigation, dating back to at least the Egyptians.

The Egyptians, the Assyrians, the Greeks and the Babylonians are all known to have made simple lenses from polished quartz crystals. It is thought that the Emperor Nero was the first monocle-wearer. In his case, it was an emerald, specially shaped, which he supposedly used to watch games in the amphitheater more clearly.

Nevertheless, there were some significant theoretical advances made in the intervening period. As usual, it was the Greeks and Romans who were most prolific in their investigations. Such thinkers as Democritus, Aristotle, Seneca and Ptolemy discovered the straightness of light rays, investigated refraction and considered the curious case of magnification (of objects seen through transparent vessels filled with water).

Some of the main ideas which persisted as a result of existent works was that light somehow emenated from the eye (which Euclid had originally proposed and which Aristotle rejected) and that color was somehow due to the roughness of the atoms of light.

Before the Renaissance, the Islamic world was the custodian of ancient knowledge which they translated, developed and passed on. Chief amongst these was Al-Kindi, who suggested that light rays were emitted from every object and thus permeated the entire world, and Ibn Sahl. The latter was the first to write in detail about the effects of curved mirrors and lenses to bend and focus light.

Important as these two were, they were eclipsed by 'the father of modern optics', Ibn al-Haytham, known also as Alhazen. He is associated with two key discoveries, the second of which was proved experimentally (a novelty in itself).. In fact, he has been referred to as the 'first scientist' because of his carefully detailed experimental approach. He first insisted that light entered into, and did not emanate from, the eye, overturning the earlier Greek theory.

The second discovery that he proved was that such rays had light and color. In proving this (with use of a camera obscura) he was also able to demonstrate that light moved in straight lines.

In the large body of his work, he not only studied the planets but the anatomy of the eye as well. Needless to say, his work was of great influence when the impetus for scientific investigation returned once more to the West.

The first to really push knowledge of optics forward was Roger Bacon, the English Franciscan.

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